String Reversal

Hello,
I have written c code for string reversal.
Program compiles without any error.
But it gives runtime error.

I am not able to catch the code in my error, Please help me.

The code is as follows.

#include <string.h>
#include <stdio.h>



int main()
{

int n_loopcount;
char *source= "Hello";
char *result= " ";
int n_count = 0;

while(*source!= '\0')
{
source++;
n_count++;
}
source--;

for ( n_loopcount = 0; n_loopcount<n_count;n_loopcount++)
{

//printf("%c\n",*source);

*result = *source;
result++;
source--;
}



printf("%s\n",*result);
}

result only has two bytes - it's not long enough to hold a copy of source.